British Colonial - London: 1902 - 1910
Sovereign - King Edward VII

On 1901 October 25th Gold Sovereigns were re-legalised for use in Ceylon by Proclamation of King Edward VII. Usage had previously revoked by proclamation on 1869 June 18th with the introduction of Decimal curreny for Ceylon.

SPECIFICATIONS
DenominationSovereign
MetalGold 0.916
AlloyAg/Cu 0.??
Diameter21.9 mm
Thickness1.4 mm
Weight Legal7.99 gms
Weight7.95 gms
ShapeRound
EdgeMilled
Die-Axis0°
MintRoyal, London
 19xx_edward~vii_1s_au_obverse 19xx_edward~vii_1s_au_reverse
Obverse : The bare bald head of King Edward~VII facing right. Around periphery legend EDWARDVS VII D: G: BRITT: OMN: REX F: D: IND: IMP: . Mint Engraver George William De Saulles placed small initials DeS in relief below the Truncation.
Reverse: St. George with Steamer flowing from Helmet, mounted on horse rearing right, slaying with sword in right hand, the dragon on ground. Mint Year below the representation of ground, with designer Benedetto Pistrucci's initials B.P. to the right.

Note that King Edward~VII, St George Sovereigns were minted with Mint mark on the representation of ground on reverse.
Royal MintStart End Mint Mark
London 1902 1910 None
Melbourne 1902 1910 M
Sydney 1902 1910 S
Perth 1902 1910 P
Ottawa 1908 1910 C

According to Proclamation sovereigns which have been issued by His Majesty's Royal Mint in England or by any branch of that Mint for the time being established, and have not been called in by any Proclamation made in pursuance of The Coinage Act, 1870, and have not been diminished in weight by wear or otherwise so as to be of less weight than the weight specified or declared for the purpose by or in pursuance of the said Act, shall be legal tender in His Majesty's Colony of Ceylon for a payment of any amount at the rate of one sovereign for fifteen rupees.

Due to unprecedented increase in Mexican silver output the world price of silver depreciated relative to gold. The Indian Silver Rupee which was worth 2 Shillings in 1870 when decimal currency was introduced in Lanka was 1s 6d by 1900,

In 1890 November a proclamation made any gold coin struck before 1837 not legal tender with effect from 28 February 1891. So sovereigns minted before 1837 were legal tender in Ceylon only before 1869.

English law allowed a sovereign to be legal tender so long as it weighs 7.93787 g (0.28 oz or 0.6% below standard weight), which gave it an average lifespan of 15 years. The Bank of England removed worn sovereigns and half sovereigns from circulation and had them recoined. Orders in Council in 1889 and 1890 permitted members of the general public to have any underweight sovereign coin replaced.

Ref: The Gold Sovereign. by M. A. Marsh.
1999, Cambridge U.K., 2nd ed. 118pp. Illustr. colour       Sovereign (British_coin) in Wikipedia

The Sovereign was scanned at 600 dpi and displayed at 300 dpi It was won on eBay in 1999 April.